Dataset Information

Melatonin promotes osteoblast differentiation by regulating Osterix protein stability and expression.

ABSTRACT: Although the biological role of melatonin in osteogenic differentiation has been suggested, the mechanism of osteoblast differentiation remains unclear. Thus, the present study investigated the underlying molecular mechanisms based on osteoblast-specific transcription factors. We found that melatonin enhanced BMP-4-induced osteogenic differentiation and increased the expression of osteogenic markers, especially Osterix, which is an essential transcription factor for the differentiation of preosteoblasts into mature osteoblasts in the late stage of osteoblast differentiation. Melatonin treatment increased the expression of Osterix during osteoblast differentiation and stabilized its expression by the inhibition of ubiquitin-proteasome-mediated degradation of Osterix, leading to up-regulated Osterix transcriptional activity on the osteogenic promoter and promoting alkaline phosphatase activity and bone mineralization. Furthermore, treatment with protein kinase A (PKA) inhibitor H89 and protein kinase C (PKC) inhibitor Go6976 blocked the melatonin-induced transcriptional activity and phosphorylation of Osterix, indicating that melatonin regulates Osterix expression via the PKA and PKC signaling pathways. Overall, these findings suggest that melatonin directly regulates the late stage of osteoblast differentiation by enhancing Osterix expression; this provides further evidence of melatonin as a potent agent for treating osteoporosis.

SUBMITTER: Han Y

PROVIDER: S-EPMC5515917 | biostudies-literature | 2017 Jul

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Melatonin promotes osteoblast differentiation by regulating Osterix protein stability and expression.

Han Younho Y Kim Young-Mi YM Kim Hyung Sik HS Lee Kwang Youl KY

Scientific reports 20170718 1

Although the biological role of melatonin in osteogenic differentiation has been suggested, the mechanism of osteoblast differentiation remains unclear. Thus, the present study investigated the underlying molecular mechanisms based on osteoblast-specific transcription factors. We found that melatonin enhanced BMP-4-induced osteogenic differentiation and increased the expression of osteogenic markers, especially Osterix, which is an essential transcription factor for the differentiation of preost ...[more]

PMID: 28720849

Similar Datasets

Project description:Commitment of Runx2-expressing precursor osteoblasts to functional osteoblasts and then to osteocytes is triggered by Osterix (Osx), which activates its target genes in those cells during bone formation. It is not yet known whether Osx has a role in remodeling the chromatin architecture of its target genes during the transition from preosteoblast to osteoblast. In testing the hypothesis that Osx is indispensable for active chromatin architecture, we first showed that in Osx-null calvarial cells occupancy of the transcriptional activators, including lysine 4 methyl transferase (Wdr5), c-Myc, and H2A.Z, at the Osx target gene Bsp was very markedly decreased. The levels of methylation of lysines 4 and 36 and acetylation of histone H3, markers for active chromatin, were also reduced at the Bsp gene in these cells. In contrast, occupancy of the transcriptional repressors HP1 and the nucleolar protein 66 (NO66), a histone demethylase previously identified as an Osx-interacting protein, was increased at the Bsp gene in Osx-null calvarial cells. Furthermore, the Bsp promoter was hypermethylated in embryonic stem (ES) cells and in embryonic day 9.5 (E9.5) embryos but was markedly hypomethylated in the calvaria of E18.5 embryos, coinciding with robust Bsp expression. In contrast, CpG methylation in the Bsp promoter remained high in Osx-null calvaria compared to Osx-wild-type calvaria. Our data also revealed that NO66 interacted with DNA Methyltransferase 1A (DNMT1A), histone deacetylase 1A (HDAC1A), and HP1, which are known to control histone and DNA methylation. In addition, HP1 stimulated the demethylase activity of NO66 for its substrates "trimethylation of histone H3 at lysine 4" (H3K4me3) and "trimethylation of histone H3 at lysine 36" (H3K36me3). Our findings strongly suggest that in the absence of Osx, the chromatin of Osx target genes is transcriptionally inactive. We propose that Osx is a molecular switch for the formation of an active chromatin state during osteoblast differentiation, whereas NO66 helps gene repression through histone demethylation and/or formation of a repressor complex, resulting in multilayered control of the chromatin architecture of specific osteoblast genes.

Project description:Dickkopf-1 (DKK1) is a powerful antagonist of canonical WNT signaling pathway, and is regarded as a biomarker for osteoporosis. Its expression is highly correlated with bone mass and osteoblasts maturation. In this study, mouse primary bone marrow cells and osteoblast cell lines were used. Luciferase reporter assay and western blotting methods were employed to validate if miRNA-433-3p epigenetically regulated DKK1 translation. Rat bone marrow derived osteoblasts were infected with lentivirus vector in which miR-433-3p was constructed. The authors constructed lentivirus mediated miRNA-433-3p stable expression and examined the alkaline phosphatase (ALP) activity and mineral deposition level in vitro. In situ hybridization method was used to observe miR-433-3p in primary osteoblasts. We built up an OVX rat model to mimic postmenopausal osteoporosis, and found aberrant circulating miR-433-3p and miR-106b, which were not reported previously. Results showed that miR-433-3p potentially regulated DKK1 mRNA, Furthermore, the correlation of serum DKK1 with circulating miR-433-3p level was significant (r = 0.7520, p = 0.046). In the luciferase reporter assay, we found that miR-433-3p siRNA decreased luminescence signal, indicating direct regulation of miR-433-3p on DKK1 mRNA. When the miR-433-3p binding site in DKK1 3'UTR was mutant, such reduction was prohibited. Western blotting result validated that miR-433-3p inhibited over 90% of DKK1 protein expression. Similarly, the change of protein expression was not observed in mutant group. The stable expression of lentivirus mediated miR-433-3p increased ALP activity and mineralization both in human and rat derived immortalized cells. We found that primary osteoblasts had higher miR-433-3p level compared with immortal cells through real-time PCR, as well as in situ hybridization experiment. Conclusively, our findings further emphasized the vital role of miR-433-3p in DKK1/WNT/?-catenin pathway through decreasing DKK1 expression and inducing osteoblasts differentiation.

Dataset Information

Melatonin promotes osteoblast differentiation by regulating Osterix protein stability and expression.

Publications

Melatonin promotes osteoblast differentiation by regulating Osterix protein stability and expression.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets